Interpolymer of isoolefine and polyolefine



Patented Apr. 15, 1947 INTERPOLYMER OF ISOOLEFINE AND POLYOLEFINEWilliam J. Sparks, Elizabeth. and Robert M. Thomas, Union. N. .L,assignors to Standard Oil Development Company, a corporation oi Dela- NoDrawing. Application September 5, 1941, Serial No. 409.658

15 Claims.

This invention relates to hydrocarbon polymers; relates particuarly tointerpolymers or oopolymers of an isoolefin with a triolefln and relatesparticularly to solid, rubbery. elastic, sulfurizable interpolymers ofan isoolefln with a tertiary polyolefin having more than two doublebonds.

As shown in our copending application, Serial No. 182.252. filedDecember 29, 1937, now Patent No. 2,356,127, it has been found possib'eto produce an interpolymer of an isoolefin such as isobutylene with aconjugated diolefin such as butadlene or isoprene or pentadiene ordimethyl butadiene by a low temperature technique, utilizing an activemetal halide, or Friedel-Crafts type, catalyst dissolved in a lowfreezing solvent. The resulting interpolymers have molecular weightsranging from 15,000 to 150,000 or higher, have iodine numbers rangingfrom 1 to 60, and are reactive with sulfur in a curln'g reaction bywhich the plasticity of the interpo'ymer is largely destroyed andreplaced by an elastic limit at which the material has a tensilestrength ranging from 2,000 to 5,000 pounds per square inch and anelongation ranging from 300% to l200%.

The resulting lnterpolymers are high grade materials suitable forreplacement of natural rubber for many of its uses. The interpolymers donot, however, have all of the characteristics of natural rubber. nor allof the characteristics desirable for some particular uses, andaccordingly, means for modifying the characteristics of the materials toadapt them to particular uses are important.

The present invention presents a new interpolymer in which an isoolefin,preferably isobutylene, or alternatively 3-methyl butene-l or 4-methylpentene-l, is interpolymerized with a tertiary triolefin or highertertiary polyolefin by the application to a mixture of the isoolefinwith the tertiary triolefin of a Friedel-Crafts catayst or dissolvedactive metal halide catalyst at low temperatures.

A suitable tertiary triolefin is found in the substance known asmyrcene, a hydrocarbon occurring naturally in bay leaf oil. Thestructure of this polyolefin is It will be observed that this is atrlolefin of which one pair of double bonds are conjugated, one doublebond is terminal and attached to a tertiary carbon atom. It is believedthat either the conjugated system or th'e'terminal doublebond attachedto a tertiary carbon atom will allowthe myrcene to enter into copolynerlz'ationwith the isobutylene, thus leaving two double bonds availablefor curing for each molecule of myrcene copolymerized. This explanationis only a. matter of theory and we do not wish to be bound by any theoryas to how the myrcene undergoes interpolymerization with the lsoolefln.

When a triolefln of this type is employed, the copolymer withlsobutylene is quite insoluble in the usual organic solvents. This ispresumably due to both of the terminal double bonds undergoingpolymerization and thus giving rise to some cross-linkage in thelnterpolymer.

As an alternative, 2,6-dimethyl-4-methyleneheptadlene-2,5, having theformula:

which is prepared from phorone and methyl magneslum iodide may also beemployed.

Other similar tertiary triolefins are likewise usable, such as 2-methy1hexatriene-1,3,5, having the formula:

These examples, as above pointed out, deal with trlolefins but theinvention is not limited to triolefins as such but? applicable to any ofthe higher olellns havin three or more double linkages in the molecule;that is, any compound having the empirical formula in which n is anywhole number greater than 5 and r is any even number greater than 2. Insuch a substance, it is essential that at least two of the double bondsbe in the conjugated relationship; or that the compound should be atertiary olefin with a terminal double bond attached to the tertiarycarbon atom: that is, the first requlrement necessitates a formula inwhich n is at least 2. a: is any uneven number an R is hydrogen or analkyl substituent. The last of the above requirements is satisfied by aformula,

in which n is any whole number, 1; is any whole number of such valuethat 11 plus 11 is greater than 3 and x is any uneven number greaterthan 1.

In fact, any polyoleflns having three or more double bonds areapplicable as long as one pair of these double bonds are conjugated orif one double bond is terminal and attached to a tertiary carbon atom.

Thus an object of the present invention is to prepare an interpolymer ofan isoolefln such as isobutylene with a polyolefin or trlolefin such asmyrcene and related hydrocarbons, to modify and improve thecharacteristics of a low temperature, rubbery interpolymer. Anotherobject is to prepare an interpolymer of isoolefin with a polyolefin inwhich a. higher chemical unsaturation can be introduced into thepolymeric body per unit of polyolefin employed in the starting feed.Other objects and details of the invention will be apparent from thefollowing description.

In practicing this invention, an olefinic mixture is prepared consistingof the isoolefin, preferably isobutylene, with the polyolefin, thelsoolefin preferably being present in the ratio of from 70 to 99 partswith the triolefln present in the ratio of 30 to 1 part. This olefinicmixture may be diluted with a diluent-refrigerant such as liquidethylene or liquid ethane or liquid methane or mixtures of these severaldiluent-refrigerants, or mixtures of them with other inert dlluents suchas liquid propane, liquid butane, liquid ethyl or methyl chloride andthe like, the diluent refrigerant being present in the proportion offrom about 1.t 5 or 6 volumes per volume of mixed oleflns.Alternatively, an excess 01' solid carbon dioxide may be utilized eitherwith or without an auxiliary diluent such as propane, ethyl or methylchloride or similar inert, low freezing substances. As anotheralternative, the olefinic mixture may be cooled by an externally appliedrefrigerant, the mixture being rapidly circulated past a cooled metalsurface, such as cooling tubes. The polymerization temperature liesbelow 0' C. and prelerably below 40 C. Temperatures 0! -78 to -100 C.,or even as low as i65 C. are desirable. The catalyst preferably consistsof an active metal halide catalyst, or a Frledel-Crafts type catalyst,such as aluminum chloride, bromide or iodide, or uranium or titaniumchloride or BF: which may advantageously be dissolved in a low freezingsolvent such as ethyl or methyl chloride or carbon disulfide or similarhomologous substance. The catalyst solution is preferably applied in afinely sub-divided form either on or below the surface of the rapidlystirred mixture of the reaction mixture. The reaction proceeds rapidlyto produce the desired solid, plastic, elastieinterpolymer.

The interpolyrner may be mixed with sulfur and appropriate fillers,plasticizers and the like, and suitable sulfurlzation aids such as Tuads(tetramethyl thiuram disulfide) by masticating on a mill. Theinterpolymer when so compounded, cures into an elastic, rubberlikesubstance having an elastic limit. a high tensile strength and a highelongation, by the application of heat within a temperature range of 100C. to 200 C. for a time interval ranging from 5 to 120 minutes.

Example 1 A mixture of 99 parts of liquid. ili llhlltylfil'lc was prepard with one part of lnjvrcrmc, and 4 volumes of liquid illljv'ltil wereadded tr; ti l: mixed oiefins. The mixture was prepared in a reactorequipped 4 with a powerful stirring device and provided with a cover toavoid contact with air. The reactor also was well insulated to reducethe rate 01 volatilizetion or the refrigerant by ambient heat. Thecatalyst was prepared by dissolving commercial anhydrous aluminumchloride in methyl chloride at the boiling point of the methyl chlorideto yield a saturated solution containing about 1.3% of materialcalculated as aluminum chloride. This solution was then diluted with anadditional amount or methyl chloride to produce a. solution containing0.5% of dissolved aluminum chloride. This solution was then precooled to-78 C. and sprayed through a spray nozzle onto the surface of thevigorously stirred mixed oieflns. The poly The interpolymer oiisobutylene and myrcene obtained in Example 1 was then compoundedaccording to the following formula:

Parts Interpolymer Zinc oxide 5 Stearic acid 8 Sulfur 3 Tuads 1 Inpreparing this compound, the inter-polymer was worked upon the mill tora time interval of approximately 5 minutes. Then the zinc oxide wasadded and thoroughly incorporated into the polymer by further working onthe mill. Thereafter, the stearic acid and sulfur were simultaneouslyadded, the mill temperature during this portion of the operation beingmaintained at approximately C. When these ingredients were thoroughlyincorporated, the mill was cooled to a temperature 01 approximately 40"C. and the Tuads added, and the compound removed from the mill.

This prepared compound was then placed in a mold and cured at a.temperature of C. for 60 minutes to produce a product which wasinsoluble in petroleum .ether and having good tensile strength andelongation properties.

Example 3 An oleflnic mixture containing isobutylene in the proportionof 98 parts of 2,6-dimethyl-4- methylene heptadiene-2,5 in theproportion of 2 parts was prepared as in Example 1 and polymerized inthe presence of liquid ethyl chloride, the mixture being cooled by soliddry ice present in the ethyl chloride solution. A solution of borontrifluoride in ethyl chloride was used as catalyst to produce aninterpolymer which was compounded as shown in Example 2 to produce astrong. elastic, rubber-like substance.

The above Examples 1 to 3 inclusive are rep resentative in characteronly and are applicable to other oleflns than the triolefin mentioned;applicable both to other trioleiins and to still higher polyolefins,such as those containing 4, 5, and

even more double bonds.

Thus the invention provides a new and useiul interpolymer of anisoolefin with a polyolefin in which the properties of the interpolymerare modified by the changes produced from the presence of the variouspolyolefins in that the interpolymers contain more chemical unsaturationover corresponding interpolymer produced from isoolefins and diolefins,and therefore possess greater sulfur reactivity.

While there are above disclosed but a limited number of embodiments ofthe invention, it is possible to produce still other embodiments withoutdeparting from the inventive concept herein disclosed, and it is,therefore, desired that only such limitations be imposed upon theappended claims as ar stated therein or required by the prior art.

The invention claimed is:

1. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps oi. reacting together a major proportion of an aliphaticiso-oleiin having 4 to 6, inclusive,

carbon atoms per molecule, with a minor proportion of a conjugatedtertiary polyolefin having more than two double bonds with one thereofcomprising a terminal double bond attached to the tertiary carbon atom,at a temperature between 0 C. and -l65 C. in the presence of apolymerization catalyst comprising a Frledel- Crafts catalyst dissolvedin a solvent which forms no complex with the Friedel-Crafts catalyst andis liqu d at the reaction temperature.

2. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic iso-olefinhaving 4 to 6, inclusive, carbon atoms per molecule, with a minorproportion of a conjugated tertiary triolefln comprising a terminaldouble linkage attached to the tertiary carbon atom. at a temperaturebetween 0 C. and -l65 C. in the presence of a polymerization catalystcomprising a Friedel-Crafts catalyst dissolved in a solvent which formsno complex with the Friedel-Crafts catalyst and is liquid at thereaction temperature.

3. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic iso-olefiuhaving 4 to 6, inclusive, carbon atoms per molecule, with a minorproportion of a conjugated polyoleiln represented by the formula inwhich n is at least 2, a: is any uneven number and R is a substituentselected from the group consisting of hydrogen and an alkyl substituent,at a temperature between 0 C. and -l65 C. in the presence of apolymerization catalyst comprising a Friedel-Craits catalyst dissolvedin a solvent which forms no complex with the Friedel- Craits catalystand is liquid at the reaction temperature.

4. The process or preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic iso-oleilnhaving 4 to 6, inclusive, carbon atoms per molecule. with a minorproportion or myrcene, at a temperature between 0 C. and l65 C. in thepresence of a polymerization catalyst comprising a Friedel-Craftscatalyst dissolved in a solvent which forms no complex with theFriedel-Crafts catalyst and is liquid at the reaction temperature.

5.'The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic iso-olefinhaving 4 to 6, inclusive, carbon atoms per molecule, with a minorproportion of 2,6-dimethyl-4-methyleneheptadiene-2,5, at a temperaturebetween 0 C. and C. in the presence of a polymerization catalystcomprising a Friedel-Crafts catalyst dissolved in a solvent which formsno complex with the Friedel- Crafts catalyst and is liquid at thereaction temperature.

6. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic iso-olefinhaving 4 to 6, inclusive, carbon atoms per molecule, with a minor proportion of 2-methyl hexatriene-1.3,5, at a temperature between 0 C. and 165C. in the presence of a polymerization catalyst comprising aFriedel-Craits catalyst dissolved in a solvent which forms no complexwith the Friedel-Cratts catalyst and is liquid at the reactiontemperature.

7. The process of preparing a solid, plastic, hydrocarbon interpolymercomprising the step of reacting together a major proportion ot a lowmolecular-weight aliphatic iso-olefln having less than 7 carbon atomsper molecule with a minor proportion of a low molecular-weight aliphaticconjugated tertiary polyolefin having more than two double bonds withone thereof comprising a terminal double bond attached to the tertiarycarbon atom in the presence of a Friedel-Craits catalys't dissolved in asolvent which forms no complex with the Friedel-Crafts catalyst and isliquid at the reaction temperature, the reaction being conducted at atemperature between 0 C. and -l65 C.

8. Th process of preparing a solid, plastic, hydrocarbon interpolymercomprising the step of reacting together a major proportion of a lowmolecuiar-weight aliphatic iso-olefin having less than '7 carbon atomsper molecule with a minor proportion 02 a low molecular-weight aliphatictriolefin comprising a, terminal double linkage attached to the tertiarycarbon atom in the presence oi a Friedel-Craits catalyst dissolved in asolvent which forms no complex with the Friedel- Crafts catalyst and isliquid at the reaction temperature; the reaction being conducted at atemperature between 0 C. and -l65" C.

9. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thestep of reacting together a. major proportion of isobutylene with aminor proportion of a low molecular-weight, aliphatic, conjugatedtrioienn in the presence of a Friedel-Crai'ts catalyst dissolved in anorganic solvent which forms no complex therewith and is liquid at thereaction temperature, the reaction being conducted at a temperaturebetween 0 C. and -l65 C.

10. The process of preparing a solid, plastic, hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thestep of reacting together a major proportion of isobutylene with a minorproportion of a low molecular-weight, aliphatic. conjugated polyoleflnrepresented by the formula in which n is at least 2, a: any unevennumber and R is a substituent selected from the group consisting ofhydrogen and an alkyl substituent, in the presence of a Friedel-Craftscatalyst dissolved in an organic solvent which forms no complextherewith and is liquid at the reaction temperature, the reaction beingconducted at a temperature between C. and --165 C.

11. The process of preparing a solid, plastic hydrocarbon interpolymerwhich is reactive with sulfur to yield an elastic product. comprisingthe step of reacting together a major proportion of isobutylene with aminor proportion of myrcenc in the presence of a Friedel-Craits catalystdissolved in a solvent which forms no complex therewith and is liquid atthe reaction temperature, the reaction being conducted at a temperaturebetween 0 C. and -l65 C.

12. The process of preparing a cured, elastic, hydrocarbon interpolymercomprising the step of reacting together a major proportion ofisobutylene with a minor proportion of myrcene in the presence of aFriedel-Crafts catalyst dissolved in a solvent which forms no complextherewith and is liquid at the reaction temperature, the reaction beingconductedat a temperature between -40 C. and l65 0., and thereafterheating the polymer with sulfur and a sulfurization aid comprisingtetramethyl thiuram disulfide.

13. A synthetic solid, plastic, hydrocarbon interpolymer of a majorproportion oi isobutylene with a minor proportion of myrcene, thepolymer being characterized by a low unsaturation below an iodine numberof 50, a molecular weight above 15,000, and reactivity with sulfur toyield an elastic product.

14. A synthetic solid, plastic, hydrocarbon interpolymer of a majorproportion of isobutylene with a minor proportion 01 a conjugatedtriolefln, the polymer being characterized by a low unsaturation belowan iodine number of 50, a molecular weight above 15,000, and reactivitywith sulfur to yield an elastic product.

15. Th process of preparing a solid plastic hydrocarbon interpolymerwhich is reactive with sulfur to give an elastic product comprising thesteps of reacting together a major proportion of an aliphatic isoolefinhaving 4 to 6 inclusive carbon atoms per molecule with a minorproportion of a conjugated polyolefin having more than 2 double bonds,at least 2 of which are in conjugated relationship, at a temperaturebetween 0 C. and -l C. in the presence of a polymerization catalystcomprising a Friedel-Crafts catalyst dissolved in a solvent which formsno complex with the Friedel-Crafts catalyst and is liquid at thereaction temperature.

WILLIAM J. SPARKS. ROBERT M. THOMAS.

REFERENCES CITED UNITED STATES PATENTS Name Date Wiezevich Sept. 3, 1940Number

